Review on performance enhancement methods of tunable diode laser absorption spectroscopy for in situ gas measurement

Tunable diode laser absorption spectroscopy (TDLAS) technology has become a prominent method of gas measurement, owing to its advantageous characteristics of high selectivity, precision, and sensitivity. In situ gas measurement using TDLAS is widely employed in marine, energy, industrial, and environmental applications, thanks to its excellent real-time performance and strong anti-interference capabilities, which enable the acquisition of more reliable and trustworthy information from gases. However, the applications across different fields are limited by several factors that affect the performance of in situ measurement. These challenges include the need to operate under harsh ambient temperatures for atmospheric and marine dissolved gas detection, the potential for cross-interference in biological breath gas measurement, and the presence of significant noise and vibration for industrial gas measurement. For the issue of in situ measurement, this paper first introduces the theoretical principle of TDLAS and then analyzes the factors that affect measurement. It provides an overview of methods and core technologies designed to enhance TDLAS performance, focusing on three critical aspects of measurement: accuracy, precision, and detection limit. Finally, it presents several case studies to demonstrate the application of TDLAS in situ gas measurement, offering a comprehensive reference using this technology across various scenarios.